Method and apparatus for printing



June 8, 1943. w, GRUPE 2,321,140

um'rnon AND APPARATUS FOR PRINTING Filed Dec. 28, 19:59

IN VENT 0R M4 04M 6A up ATTORNEY Patented June 8, 1943 METHOD ANDAPPARATUS FOR PRINTING William F. Grupe, Lyndhurst, N. J., assignor toInterchemical Corporation, New York, N. Y., a

corporation of Ohio Application December 28, 1939, Serial No. 311,349

8 Claims. (01. 1o1 41s) This invention relates to printing, andparticularly to an improved method and apparatus for printing which willinsure rapid drying of the printed surface, and which will minimize orentirely prevent offsetting.

Film forming compositions, such as printing inks, are applied to websand sheets of paper, textiles and the like-in a liquid state, and aredried by conversion into solid form. Depending upon the ingredientsincluded in the film forming composition, the conversion required fordrying usually may be effected by cooling, oxidation, evaporationofsolvent, or polymerization. However, recently it has been suggested thatprintinginks, for example, may be dried or set by incorporating into thewet film of ink a thickener which is soluble in the film. The thickenerorsetting medium is preferably one for which the ingredients of the inkfilm have a low solvent volatile solvent which is miscible with the filmvehicle. Then upon evaporation of the added solvent, the mixture in thefilm changes from the liquid state to the solid and thus dries.

Heretofore the wet. ink has been impregnated with the thickener orsetting medium by spraying the latter upon the freshlyprinted sheet orweb or applying it thereto with a conventional coating roller. Thismanner of application causes the loss of large quantities of the sprayedor coated material and has other disadvantages. One particularlyimportant disadvantage is that the type of material now used tends torepel the presently used adhesives so that the finished sheets or webcannotbe used subsequently in making up bags immediately afterapplication there will be no danger of offsetting. My improved methodcomprises applying a, film of printing ink and a film forming or settingmaterial which is soluble in the ink to a printing member, and thentransferring the ink and the film forming material to the surface of asheetv or web. This method may be practiced either by applying the filmforming material to the type before the ink is applied, or by applyingit directly after the ink is applied, and, due to the fact that thepress is operating at high-speed and the consequent lack of time to loseor evaporate any solventin the film forming material, setting of the inkwill not take place until it has been transferred to the sheet which maybe subsequently heated, if desired. The application of the film formingmaterial may be accomplished by means of a suitable coating roller whichis adapted or positioned to apply the material either directly before ordirectly after inking of the type. In this manner, the ink settingmaterial is only applied to the printed matter and a great saving iseffected.

The above and other features and objects of the present invention willbecomeapparent upon consideration ofthe following detailed descriptionand the accompanying drawing in which: Fig. 1' is a diagrammatic sideelevaticnal view of an apparatus embodying my invention and useful inthe practice of that form of my method in which the ink setting materialis applied after the type hasbeen inked;

Fig. 2 is an enlarged fragmentary vertical elevational view of a part ofthe apparatus illustrated in Fig. 1; and

Fig. 3 is a diagrammatic side elevational view, similar to Fig. 1,showing a modified form of apparatus embodying my invention, and inwhich the ink setting medium is applied in a film to the type prior tothe inking thereof.

Referring-now to the drawing, it will be observed that a web ll], ofpaper or other suitable material to be imprinted, is fed from a suitablesupply roll l2 by means of conventional feed rollers it through aprinting unit It. The printing unit l8, which'may be of any suitableconstruction, includes an impression cylinder It, a. cooperating plateor printing cylinder 20, and an ink applying and distributing system ofrollers 22. The ink applying and distributing system of rollers 22functions to a ply a uniform film'24 of ink of the desired thickness tothe type 26 of the printing cylinder 20 as indicated in Fig. 2 and, inthe ordinary printing press, such film would be applied in the usualmanner to the web in during operation of the press. In the presentconstruction, however, I have provided a coatin roller 28, which ispositioned between the ink applying rollers 22 and the web, formodifying the conventional practice in accordance with my insettingmaterial which has been found suitable for application in the mannerherein described, is that disclosed in Adolph J. Pingarron Patent No.2,249,782, dated July 22, 1941, and consists of solutions of a rapidlyvolatilizable solvent miscible with the ink vehicle and a dissolved filmforming solid. for which the ink vehicle has a low solvent power. Aspecific solution of this character, which may be used for drying aconventional linseed oil ink, may comprise a five percent solution ofhigh viscosity (1000 centipoise) chlorinated rubber (sold under thetrade name Tornesit" in toluol. The solution of chlorinated rubber mixeswith the wet ink film, and

- upon evaporation of the toluol, which occurs in a few seconds, thefilm becomes a. dispersion of pigment in a solution of chlorinatedrubber in the particular linseed oil used in the ink. Since suchsolutions are highly viscous masses at room temperature when the amountof chlorinated rubber exceeds one pe'rcent, and since such viscousmasses, when pigmented, are essentially solid, the ink is dry when thetoluol evaporates. Although further drying occurs by oxidation, the inkis dry enough to permit reverse side printing within a few seconds afterthe chlorinated rubber solution has been applied.

During normal operation of the ordinary printing press, such as thatshown in Fig. 1, the application of the ink setting material to the typein the manner described and the subsequent application of the ink thustreated to the upper surface of the web 0 will cause the ink to setrapidly so that said web may be subsequently severed into individualsheets and delivered without smudging or offsetting. However, when thepress is operating at speeds above one hundred feet per minute, eventhough some of the solvent is absorbed by the paper, it may be desirableto provide a means 36 beyond the printing unit 16 for directing a blastof heat upon the printed and treated surface. This heat may beadvantageously applied by means of an ordinary gas burner adapted toproduce an elongated flame or it may be applied in the form of a blastof hot air, either of which is adapted to drive of: the remainingsolvent without raising the temperature of the sheet over 200 F. Beingthus thoroughly dried the printed web may be given any desiredsubsequent treatment, or it may be rewound upon a suitable rewind rollstand 38.

In Fig. 3, I have shown a construction similar in all respects to thatshown in Fig. 1, except that the ink setting material is applied to thetype immediately after printing and prior to inking, rather thansubsequent to inking as in the Fig. 1 construction. As shown in Fig. 3,a web 40 of paper, or other suitable material to be printed, is fed froma suitable supply roll 42 by means of conventional feed rollers 44 to aprinting unit 46 which includes a printing cylinder 48 and an inkapplying and distributing system 50. A coating apparatus 52 of anysuitable construction is D0- sitioned on the right hand side of theprinting or plate cylinder 48 for applying a film of ink settingmaterial to the type prior to the inking of said type by the inkapplying and distributing system 50. With this construction the inksetting medium will first be applied and then the type will be inked andthe combined ink and ink setting material is applied to the web duringoperation of the printing press. As in the Fig. 1 construction, theprinted web may be given a heat treatment by a suitable heating device54 prior to its being rewound upon a rewind reel 56.

From the foregoing, it will be understood that with either the Fig. 1 orFig. 3 construction, the type of the plate or printing cylinder iscoated with a film of ink and with a film of ink setting material andthe two films are then transferred to the surface of the material beingprinted. By operating in this manner, there is a saving of at leasttwenty percent of the ink setting material that would be used in theprior methods of setting ink, and the ink setting material is onlyapplied to the ink so that all unprinted portions of the sheet willbecompletely clean and receptive to adhesives or other materials that maybe applied or used thereon in the subsequent treatment of the web.

While I have described preferred embodiments of the apparatus featuresof my invention, and have shown a conventional double roller type ofcoating apparatus for applying the film of ink setting material, it willbe readily understood that other forms of coating apparatus may be usedin the practice of my invention. Moreover, various other changes may bemade in the apparatus or method herein described and certain features orsteps thereof may be employed without others, without departing from myinvention or sacrificing any of its advantages.

What I claim is:

1. A method of printing which comprises applying a film ofprinting inkand a film of a film forming material which is soluble in the ink to aprinting member, and then transferring the ink and film forming materialto the surface of a sheet or web.

2. A method of printing which comprises applying a film of ink to aprinting member, incorporating into said ink a film forming solid whichis soluble in the ink and causes it to set, and then transferring thethus treated ink to the surface of a sheet or web.

3. A method of printing which comprises applying a film of an inksetting medium to a printing member, applying a film of ink to saidprinting member, and then transferring both of said films to the surfaceof a sheet or web.

4. Apparatus for printing, comprising a printing cylinder having typethereon; an impression cylinder cooperating with said printing cylinder;an ink distributing system for applying a uniform film of ink to saidtype; roller coating means, disposed adjacent said printing cylinderbetween said ink distributing system and the impression line between theprinting and impression cylinder in the direction of rotation of saidprinting cylinder, for applying a film of an ink setting medium to theinked type; means for feeding a web between said printing and impressioncylinders; and means for applying heat to the freshly printed web.

'5. A method of printing which comprises applying a film of printing inkand a film of a film forming material which is soluble in the ink to aprinting member, transferring the ink and film forming material to thesurface of a sheet or web, and applying heat to said sheetor web.

6. A method of printing which comprises applying a film of ink to aprinting member, adding to said film a solution of a rapidlyvolatilizable solvent miscible with the ink vehicle and a dissolved filmforming solid for which the ink vehicle ha a low solvent power, and thentransferring the thus treated ink to the surface of a sheet or web.

7. A method of printing which comprises applying a film of linseed oilink to a printing memsaid sheet or web.

WIILIAM F. GRUPE.

